In situ structures of the segmented genome and RNA polymerase complex inside a dsRNA virus.

Viruses in the Reoviridae, like the triple-shelled human rotavirus and the single-shelled insect cytoplasmic polyhedrosis virus (CPV), all package a genome of segmented double-stranded RNAs (dsRNAs) inside the viral capsid and carry out endogenous messenger RNA synthesis through a transcriptional enzyme complex (TEC). By direct electron-counting cryoelectron microscopy and asymmetric reconstruction, we have determined the organization of the dsRNA genome inside quiescent CPV (q-CPV) and the in situ atomic structures of TEC within CPV in both quiescent and transcribing (t-CPV) states. We show that the ten segmented dsRNAs in CPV are organized with ten TECs in a specific, non-symmetric manner, with each dsRNA segment attached directly to a TEC. The TEC consists of two extensively interacting subunits: an RNA-dependent RNA polymerase (RdRP) and an NTPase VP4. We find that the bracelet domain of RdRP undergoes marked conformational change when q-CPV is converted to t-CPV, leading to formation of the RNA template entry channel and access to the polymerase active site. An amino-terminal helix from each of two subunits of the capsid shell protein (CSP) interacts with VP4 and RdRP. These findings establish the link between sensing of environmental cues by the external proteins and activation of endogenous RNA transcription by the TEC inside the virus

Hydroclimatic risk to economic growth in Sub-Saharan Africa

In order to plan strategies for adaptation to climate change, the current effects of climate on economic growth needs to be understood. This study reviews evidence of climate effects on economic growth and presents original analysis of the effect in Sub-Saharan Africa (SSA). Case studies from the literature demonstrate that historically, climate has had significant and negative effects on household income, agricultural productivity and economic growth in SSA. This study focuses on the effects hydroclimatic variability on economic growth in the countries of SSA. We utilize a new national level precipitation statistic that incorporates spatial and temporal variability within each country. Country level economic growth statistics are analyzed with cross-country and panel regressions. Persistent negative precipitation anomalies (drought) are found to be the most significant climate influence on economic growth. This result is consistent across all model specifications and across several measures of welfare and economic activity. Temperature and precipitation variability show significant effects in some cases. Results imply the consideration of hydroclimatic risks, namely drought, may be the priority concern for adaptation to a changing climate for Sub-Saharan Africa. This conclusion is contrary to the focus of many climate change impact assessments that focus on temperature increases as the primary concern

A US-India Example in Case History Use in Levee Safety — A Multi-Cultural Perception of What It Is, and How Should It Be Applied

The State of Bihar, India experienced substantial flooding in the Ganges Basin as a result of levee (embankment) non performance. As a result of the 2008 failures the Bihar Water Resources Department is examining, as a programmatic model, the US experience in establishing and conducting the United States Army Corps of Engineers (USACE) Levee Safety Program. This case model examination is intended to structure a new program for managing the Bihari embankment infrastructure. Similar to many historical flood control initiatives throughout the world, India’s embankment infrastructure shows the effects of aging and multi-purpose use of the facilities. To examine what practices that could be employed to increase the reliable performance of the embankment system; the World Bank facilitated a detailed case history examination of the USACE Levee Safety Program. The case study included a trial application of elements of the US approach to Indian Levee systems in order to stimulate discussion of what elements could be and should be incorporated into the Indian embankment management system. Elements of the levee safety program examined in this case study include the development of a comprehensive database of features and information on the embankments, a data viewer, areas of maintenance issues and corrective maintenance management activities

Exploring the effect of hydroclimate variability on economic growth in Sub-Saharan Africa: A water security index

Recent econometric studies provide evidence that climate variability in general, and rainfall variability in particular, has a negative effect on economic growth in the countries of Sub-Saharan Africa. In this study, we explore the factors that may explain why some countries are more resilient to climate variability than others. We use a range of data that is representative of the possible sources of resilience that are commonly hypothesized in the literature, including the state of water resources and water use, the inventory of infrastructure and the quality of institutions. Two analyses are undertaken. In the first, cross country regressions are used to explore aggregate associations of climate and resilience variables with economic growth. In the second, panel regressions for individual countries are performed with drought and flood indices. The results of these regressions are used to specify a water security index. The water security index is then analyzed through the prism of the resilience variables to draw inferences in regard to the sources of resilience that contribute to more water security. The results of these analyses are informative. Cross country regressions confirm the negative association between rainfall variability and economic growth within Sub-Saharan Africa. They also revealed strong associations between Foreign Direct Investment (FDI) and infrastructure inventory and economic growth. An index that accounts for climate variability and water storage (Seasonal Storage Index) is also strongly associated with both FDI and economic growth. The analysis of the Water Security Index revealed that more internal renewable water resources and irrigated agriculture as a percent of agricultural area were associated with more resilience to hydroclimate variability. Water storage was not a strong indicator of resilience, although when controlling for hydrologic variability with the SSI, it does become more important. There were no strong associations with institutions and weak positive associations with road density and phones